The biology of tumor growth in the non-Hodgkin's lymphomas. A dual parameter flow cytometry study of 220 cases.

Dual parameter flow cytometry studies (cell DNA content and electronic cell volume) were performed in 220 cases of non-Hodgkin's lymphoma. All cases were characterized as B or T cell malignancies, based on immunologic surface marker characteristics. Aneuploidy by flow cytometry was more common among the B cell lymphomas than among the T cell lymphomas, and was most common among the large B cell lymphomas and B cell lymphomas of intermediate size. Ploidy index distributions showed a prominent hyperdiploid peak, as well as tumor cell populations with near-tetraploid DNA contents. In serial studies, a decrease in ploidy index was observed in association with clinical and histologic transformation in one case. The highest S fractions were observed among the large and intermediate B cell lymphomas and among the aggressive T cell lymphomas. In clinical samples consisting of mixtures of diploid and aneuploid populations, the data on the aneuploid components could often be separated from other components of the mixture in multiparameter studies on the basis of the larger electronic cell volumes of the aneuploid cells. In each case, the aneuploid large cell component almost invariably had a higher S fraction than the residual component(s) of the mixture. Overall, the data are consistent with a model of clonal selection and clonal evolution in the lymphomas in which early cytogenetic abnormalities that involve little or no change in total cell DNA content are followed by cell tetraploidization that is associated with cytogenetic instability and chromosome loss over the course of time.

Schedule dependence of vincristine lethality in Sarcoma 180 cells following partial synchronization with hydroxyurea.

The effects of exposure to 0.1, 0.5, or 2 microM vincristine for 4 hr were studied in Sarcoma 180 cells at various times after synchronization with 5 mM hydroxyurea for 1 hr. Maximum sensitivity to the lethal effects of vincristine was observed at 10 to 14 hr after hydroxyurea exposure at the higher vincristine concentrations, compared to a period of a maximum sensitivity to a second dose of hydroxyurea at 8 to 12 hr. Serial flow cytometry studies indicated that the apparent decrease in sensitivity to vincristine at 14 to 18 hr was due to the division of cells in the leading segment of the synchronized wave and their entry into the relatively resistant G1 phase prior to vincristine exposure. Synchronized cells that had not divided at the time of vincristine exposure were blocked transiently in G2. Serial metaphase index studies suggested that the G2 cells closest to the end of the cell cycle at the time of vincristine exposure were likely to exhibit the greatest degree of mitotic disorganization when they overcame the G2 block and entered metaphase. The present studies suggest that sensitivity to vincristine increases progressively as cells approach mitosis. The molecular mechanisms underlying this phenomenon are considered in relation to the increase in cell tubulin content during the course of cell cycle progression.

Effects of vincristine on cell survival, cell cycle progression, and mitotic accumulation in asynchronously growing Sarcoma 180 cells.

The effects of vincristine (VCR) on cell survival, cell cycle progression, DNA synthesis, and metaphase accumulation were studied in relation to drug concentration and drug exposure duration in Sarcoma 180 cells in vitro. VCR was found to affect cells in interphase, producing a transient G2 block at all drug concentrations and drug exposure durations studied. VCR did not affect DNA synthesis directly. Increases in the metaphase index were delayed and always peaked at approximately 8 hr after drug removal, regardless of the duration of drug exposure. Increases in the metaphase index of sufficient magnitude to be commensurate with VCR lethality were observed only with prolonged drug exposure. VCR produced both nuclear fragmentation and polyploidy. The proportion of cells undergoing polyploidy increased progressively with increasing drug exposure duration. Interference with cytokinesis during prolonged VCR exposure may represent a lethal effect of VCR that is separate from its short-term effects. This could serve as the basis for the clinical study of the antitumor effects of prolonged VCR infusions.

Low-frequency oscillations of cortical oxidative metabolism in waking and sleep.

To study the changes in cortical oxidative metabolism and blood volume during behavioral state transitions, we employed reflectance spectrophotometry of the cortical cytochrome c oxidase (cyt aa3) redox state and blood volume in unanesthetized cats implanted with bilateral cortical windows and EEG electrodes. Continuous oscillations in the redox state and blood volume (approximately 9/min) were observed during waking and sleep. These primarily metabolic oscillations of relatively high amplitude were usually synchronous in homotopic cortical areas, and persisted during barbiturate-induced electrocortical silence. Their mean amplitude and frequency did not vary across different behavioral/EEG states, although the mean levels of cyt aa3 oxidation and blood volume during rapid eye movement (REM) sleep significantly exceeded those during waking and slow-wave sleep. These data suggest the existence of a spontaneously oscillating metabolic phenomenon in cortex that is not directly related to neuroelectric activity. A superimposed increase in cortical oxidative metabolism and blood volume occurs during REM sleep. Experimental data concerning cerebral metabolism and blood flow that are obtained by clinical methods that employ relatively long sample acquisition times should therefore be interpreted with caution.

Early fetal movement: a real-time ultrasound study.

A single-transducer mechanical sector scanner was used to examine the first-trimester fetus. Fifty-six examinations of 31 patients demonstrated an orderly developmental progression of fetal activity beginning with beating of the fetal heart (7 weeks), progressing to fetal trunk movement (8 weeks), and culminating in individual fetal limb movement (9 weeks). The mechanical sector real-time scanner is capable of providing a high-resolution image of the first-trimester fetus and the earliest fetal movements.

NADH fluorescence, [K+]0 and oxygen consumption in cat cerebral cortex during direct cortical stimulation.

NADH fluorescence, sagittal sinus blood flow and sinus hemoglobin saturation were monitored simultaneously during direct cortical stimulation of a wide area of the anterior and mid suprasylvian and marginal gyri. The area monitored flurorometrically was located within the area apparently drained by the sinus, so that the flurometric changes could be correlated with oxygen consumption changes calculated from the sinus flow and saturation values. The onset and peak values of calculated oxygen consumption and NADH fluorescence changes usually occurred within several seconds of one another and high, significant (r greater than 0.9 and P less than 0.01) correlations were found between the maximum changes in both parameters following stimulation. The relation of cortical [K+]0 changes to oxygen consumption changes was also explored; again the magnitude of [K+]0 changes and calculated oxygen consumption changes correlated well. The demonstrated agreement between fluorometric and direct (sinus cannulation) measurements of oxidative metabolism reinforces the interpretation of in situ cortical fluorescence changes as indicative of changes in oxygen consumption rate

The contribution of local blood flow to the rapid clearance of potassium from the cortical extracellular space.

The transport of potassium to the blood stream following stimulation of the cortex in cats is evaluated by means of a potassium sensitive microelectrode technique. Potassium levels are measured in cortical veins, the sagittal sinus and the extracellular space during and after both pharmacological and electrical stimulation of the cortex. It is concluded that the potassium transport to the blood stream is not a significant factor in the rapid clearance of potassium from the extracellular space following stimulation.

A simplified method for monitoring the cytochrome aa3 redox state in bilateral cortical areas of unanesthetized cats.

We describe a versatile optical system that enables the simultaneous monitoring of the redox state of cytochrome c oxidase (cytochrome aa3) in two homologous cortical areas under chronically implanted windows in cats. A single light source, broad bandpass primary filters, light-conducting rods, and narrow-bandpass interference detecting filters are employed. We observed reproducible responses of the cytochrome redox state and blood volume to carotid occlusion and terminal anoxia during anesthesia, and to graded doses of pentobarbital in awake animals.

Interhemispheric synchrony of slow oscillations of cortical blood volume and cytochrome aa3 redox state in unanesthetized rabbits.

In order to study spontaneous, slow oscillations of regional oxidative metabolism and blood flow in the normal, unanesthetized cortex, adult rabbits were implanted with bilateral cortical windows and electrodes for polysomnography. Relative changes in the cortical intramitochondrial redox state of cytochrome aa3 (CYT) and blood volume (CBV) were monitored by dual-wavelength reflectance spectrophotometry. Continuous, non-stationary oscillations (< 0.5 Hz) of both CYT and CBV were observed during waking and non-REM sleep. Cross-correlation analysis revealed a predominant interhemispheric synchrony of these oscillations which were unrelated to the heart rate, breathing, or electrocorticogram pattern. These findings suggest a dynamic linkage of slowly varying metabolic and vascular processes between unanesthetized cortical regions of 50 mm2 surface area.

Apparent unilateral visual neglect in MPTP-hemiparkinsonian monkeys is due to delayed initiation of motion.

Monkeys made hemiparkinsonian by infusion of a solution of MPTP into one carotid artery appeared to ignore food presented from the contralateral side. Initial observations suggested neglect of visual stimuli presented as fruit treats by automated delivery system in the half-field contralateral to MPTP treatment. Further studies in which fruit treats were left in the 'neglected' visual field indicated that this apparent neglect, unlike neglect attending cortical lesions, was rather a marked delay in initiating movements (unilateral hypokinesia). These observations may explain apparent subcortical neglect and are consistent with the known role of nigrostriatal dopaminergic neurones in movement regulation. This is a useful animal model in which difficulties in initiation of movement (hypokinesia). a cardinal symptom of Parkinson's disease, can be studied separately from other deficits in motor performance.

Fluorometric monitoring of NADH levels in cerebral cortex: preliminary observations in human epilepsy.

In 14 patients operated upon for focal cerebral seizures under local anesthesia, cortical electrical activity was compared with the levels of nicotinamide adenine dinucleotide (NADH) observed fluorometrically. NADH levels fell 3 to 15% in response to 5-second intervals of cortical stimulation in 42 of 70 observations. Although a rough correlation was seen between the quantity of current delivered (milliamperes X seconds) and the NADH decrease, this varied from case to case. The presence of cortical afterdischarge often, but not invariably, corresponded to a greater percentage of change in the NADH levels. Averaging the NADH response to sporadic interictal epileptiform discharges failed to demonstrate concomitant NADH reductions. A similar lack of change was seen in four patients in whom low frequency spike foci were induced by topically applied penicillin in cortex destined for excision. Preliminary studies of the topography of spread of NADH change after cortical stimulation indicate that this is usually asymmetrical in human epileptogenic cortex. Under experimental conditions in cats, it seemed possible to differentiate primary from projected epileptiform activity, in that the projected activity had little or no concomitant fall in the NADH level after the electrographic spike. Pathological examination of the excised sites of NADH recording showed, with one exception, fibrous astrocytic transformation of the central cortex layers.

An iterative method for the deconvolution of microcalorimeter thermograms.

An iterative method for the deconvolution of microcalorimetry thermograms suitable for small digital computers is presented. The method employs a measured impulse response function directly as the deconvolution kernel, thus explicit system simulation is not required. Data are presented showing the performance of the method and the exchange of signal-to-noise ratio for time resolution that is made when deconvolution techniques are employed. An improvement in the system time resolution of fifty times is demonstrated with measured data.

The pupil dark response in normal volunteers.

A new semi-automatic videopupillometer with a two-channel video integrator uses prismatic displacement of pupil images for binocular recording with a single infrared-sensitive video camera. The video integrator graphically records pupil area or diameter during testing and can reanalyze and plot information from videotape recordings of pupil responses. This new pupillometer was used to evaluate the pupil dark response in 178 eyes of 89 normal human volunteers (ages 18-75 years). The time course of pupil dilation was similar in volunteers of all ages, even though the average pupil area became progressively smaller with increasing age.

Slow oscillations of cytochrome oxidase redox state and blood volume in unanesthetized cat and rabbit cortex. Interhemispheric synchrony.

The purpose of this study was to determine the frequency characteristics and the degree of interhemispheric synchrony of slow (< 0.5 Hz), spontaneous oscillations of the regional cortical cytochrome oxidase redox state (CYT) and blood volume (CBV) in unanesthetized animals. We implanted bilateral cortical windows and electrodes for polysomnography in 7 cats and 3 rabbits. The animals were atraumatically restrained during multiple 3-6 hour sessions for up to 8 weeks, and relative changes in the cortical CYT and CBV were monitored by dual wavelength reflectance spectrophotometry at 603 nm and 590 nm. Continuous oscillations of CYT and CBV, unrelated to pulse or respiration, were always observed in each animal. Frequency (FFT) analysis over time revealed a nonstationary distribution of frequencies below 0.4 Hz, with most of the spectral power being contained in the 0-0.25 Hz band during both waking and sleep. Although the time-frequency plots of the CYT and CBV signals were similar, an occasional dissociation between the CYT and CBV oscillations was found. Analysis of simultaneous bilateral cortical optical recordings revealed a significant and sustained interhemispheric cross-correlation over time between the CYT as well as the CBV oscillations during stable recordings as long as 60 min. We conclude that: 1) CYT and CBV levels normally oscillate at < 0.4 Hz in the unanesthetized cat and rabbit cortex; 2) these complex oscillations, whose frequencies are non-stationary over time, nevertheless show sustained interhemispheric synchrony between 50 mm2 homotopic cortical regions; and 3) these oscillations may in part represent fluctuations of the metabolic rate.